16. State to which side of the ship, in the majority of cases, is the North point of the Compass drawn in the Northern Hemisphere, and what effect it has on the aasumed position of the ship when she is steering on Northerly, and also on Southerly courses.

The North point is drawn to the weather side. Its effect is to throw the ship to windward of her course on Northerly courses, and to leeward on Southerly courses.

17. The effect being as you state, on what courses would you keep away, and on what courses would you keep closer to the wind in order to make good a given compass course? Keep away on Northerly, and keep closer on Southerly

courses.

18. Does the same rule hold good in both hemispheres with regard to the heeling error?

No in the Southern hemisphere the South end of the needle is drawn to the weather side; but neither rule is always true, observation is the only way of telling.

19. Your steering compass having a large error, how would you proceed to correct the compass by compensating magnets and soft iron, in order to reduce the error within manageable limits?

Through the centre of the binnacle draw on the deck two lines at right angles to each other, one fore-and-aft, the other athwart-ships. Put the ship's head N, (cor. mag.) place a magnet with its centre on the fore-and-aft line, and parallel to the athwart-ships line. Move it to or from the

compass till the compass shews the ship's head N. Fix the magnet in this position. Put the ship's head E, (cor. mag.) place another magnet with its centre on the athwart-ships line, and parallel to the fore-and-aft line. Move it to or from the compass till the compass shews the ship's head E. Fix this magnet also. The north poles of these magnets should point in the same direction as the North of the needle is drawn. Put the ship's head NE, (cor. mag.) place two boxes, one to port, the other to starboard, of the compass, and on the same level with it. Put sufficient soft iron in these boxes till the compass is again correct.

And shew by diagrams how these magnets and this soft iron are placed.

1st Diagram. Ship's head North or South (Cor. Mag.)

In A, the North point of the compass is drawn towards the starboard side (+C), the compensating magnet's North pole must point also towards the starboard side.

In B, the North point is drawn towards the port side of the compass (-C), the compensating magnet's North pole must point also towards the port side.

2nd Diagram. Ship's head East or West (Cor. Mag.)

In H the North point of the compass is drawn towards the bows (+B), the compensating magnet's North pole must also point towards the bows.

In K the North point of the compass is drawn towards the stern (B), the compensating magnet's North pole must also point towards the stern.

3rd Diagram. Ship's head NE (Cor. Mag.)

When the ship's

M represents the quadrantal deviation. head is placed NE or SW, the North point of the compass is drawn to the right as in the diagram; but when her head is NW or SE, the North point of the compass is drawn to the left.

In our diagram the box of soft iron (a) draws the North point back towards the left, and the box (b) draws the South point to the right, and consequently turns the North point also to the left.

M

HEELING ERROR.

The full lines in P and Q represent the ship when upright, and the dotted lines represent her when heeled. 10° to starboard, the ship's head having been placed at North when she was on an even keel, and the ship is supposed to be in North latitude.

In P, the North point of the needle is drawn to windward, which is most frequently the case, then the errror is compensated by a magnet placed vertically under the centre of the card with its North pole upwards.

In Q, the North point of the needle is drawn to leeward, in this case the magnet must be placed with its South pole upwards.